Ryoko Harada
Fukuoka University
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Featured researches published by Ryoko Harada.
Biochemical and Biophysical Research Communications | 1989
Noriko Okada; Ryoko Harada; Ryo Taguchi; Hidechika Okada
20 KDa homologous restriction factor (HRF20) is a membrane glycoprotein which inhibits formation of membrane attack complexes of homologous complement. Erythrocytes from a patient who is completely deficient in HRF20 were readily hemolyzed by homologous complement activated by sucrose or by acidification as in paroxysmal nocturnal hemoglobinuria (PNH). After incubating PNH erythrocytes (PNH-E) with purified HRF20, the cells were analyzed by flow cytometry using a monoclonal antibody to HRF20 and shown to have the antigen absorbed. These PNH-E acquired resistance to hemolysis by homologous complement suggesting that HRF20 may be successfully used for treatment of these patients.
Clinical and Experimental Immunology | 2008
Noriko Okada; Ryoko Harada; Hidechika Okada
A 20‐kD homologous restriction factor (HRF20) which is a membrane inhibitor of the terminal stage of human complement action can be detected by the monoclonal antibody IF5, and is deficient on abnormal erythrocytes as well as leucocytes from patients with paroxysmal nocturnal haemoglobinuria (PNH). The erythrocytes of PNH patients significantly improved their resistance to homologous complement after adsorption of purified HRF20.
Biochimica et Biophysica Acta | 1990
Hong Ying; Keijiro Saku; Ryoko Harada; Noboru Takami; Norihiro Sasaki; Yyasushi Saito; Kikuo Arakawa
Probucol is a widely prescribed lipid-lowering agent, the major effects of which are to lower cholesterol in both low- and high-density lipoproteins (LDL and HDL, respectively). The mechanism of action of probucol on HDL apolipoprotein (apo) A-I kinetics was investigated in rabbits, with or without cholesterol feeding. 125I-labeled HDL was injected intravenously, and blood samples were taken periodically for 6 days. Kinetic parameters were calculated from the apo A-I-specific radioactivity decay curves. Fractional catabolic rate (FCR) and synthetic rate (SR) of apo A-I in rabbits fed a normal chow and normal chow with 1% probucol were similar. Apo A-I FCR of the rabbits fed 0.5% cholesterol was significantly increased but there were no changes in SR, compared to findings in the normal chow-fed group. Apo A-I FCR of the rabbits fed 1% probucol with 0.5% cholesterol (both 1 month and 2 months) was significantly increased compared to findings in rabbits fed the normal chow as well as 0.5% cholesterol diet group, while SR of apo A-I was significantly reduced in the former groups. Kinetics at 1 month after discontinuation of 1% probucol (under cholesterol feeding) showed a similar FCR of HDL-apo A-I to that of the rabbits fed 0.5% cholesterol, but the SR of apo A-I remained lower. Apo A-I isoproteins kinetics assessed by autoradiography of isoelectric focusing slab gels showed that the synthesis of proapo A-I was significantly reduced in the 1% probucol with 0.5% cholesterol administered, compared to the 0.5% cholesterol group. Thus, the action of probucol on HDL apo A-I kinetics was only prominent in case of higher serum cholesterol levels. The decreased HDL or apo A-I seen with probucol was apparently the result of an increase in FCR and a decrease in SR of HDL-apo A-I. A decreased synthesis of apo A-I remained evident even 1 month after discontinuing probucol. The action of probucol on the intracellular synthetic processes of apo A-I was revealed by the reduced synthesis of proapo A-I.
International Immunology | 1989
Noriko Okada; Ryoko Harada; Teizo Fujita; Hidechika Okada
Journal of Immunology | 1989
Noriko Okada; Ryoko Harada; Teizo Fujita; Hidechika Okada
Journal of Immunology | 1990
Ryoko Harada; Noriko Okada; Teizo Fujita; Hidechika Okada
Journal of Biochemistry | 1990
Yoshitaka Tanaka; Ryoko Harada; Masaru Himeno; Keitaro Kato
Clinical Therapeutics | 1991
Keijiro Saku; Kazuhiko Yoshinaga; Yoshifumi Okura; Hong Ying; Ryoko Harada; Kikuo Arakawa
Atherosclerosis | 1990
Keijiro Saku; Ryoko Harada; Kyosuku Yamamoto; Hong Ying; Iwata Ozaki; Kikuo Arakawa
Japanese Journal of Rheumatism and Joint Surgery | 1990
Eisuke Shono; Noriko Okada; Misao Matsushita; Teru Hideshima; Ryoko Harada; Mitsuru Takesita; Nahoto Takagishi; Hidechika Okada